Stripped Oil Tank Vent Bolt

Well, the previous owner of my '09 YZ250F happened to strip out the oil tank vent bolt hole. It seeps a small amount of oil when I ride, as the bolt obviously won't tighten up. I'm thinking of taking the tank off and tapping the hole out to the next size up then flushing out the tank? Anyone had this happen to them before? Any input is appreciated. Thanks!

I've heard of people talk about all the time in the General Discussion area and that seems to be the standard thing to do. A little tip is to put grease on the drill bit and tap and that will help attract some of the metal shavings

Alright, thanks for the tip Swede!


Please let us know how this turns out for you. I've got the same problem.


I had the same problem. I just took a steel bolt slightly larger and than the stock aluminum one and ran it in. The steel will cut new threads in the aluminum no problem and its easier than trying to keep chips out with a tap. Going strong for 6 months.

Definitely pull the oil tank off the bike, drill and tap new threads, then flush out the oil tank really good, then install back onto the bike.

Drill the new bolt and safety wire it from now on, doing this you will not have to worry about over tightening it in the future. The bolt is easy to drill and I have personally witnessed two people who have lost that bolt while riding.

All of them should be safety wired. Loosing any one of the 3 oil bolts can cause more damage within a few minutes of falling out than dropping your valves.

samething happened to me. My dealer offered me a free oil tank removal kit beacause thier shop is backed up for three weeks, and sadly I do not have the right tools for the fix yet! has anyone here used one?

I would personally get rid of the oil tank. Its just another area where the bike can fail and leave you with a DNF or a long walk back to your truck.

I made my own wet sump kit that i modelled after dr.d's wet sump kit. It works great and I have had no problems with it. It saves around 3 pounds and its one less spot that oil can leak.

I had the same problem myself. I heli-coiled the thread with no problems. I had grease on the drill bit, and had the oil tank situated in the vise so the vent hole where i was drilling was pointing down. I also wahed it out in a solvent tank about 3 times and blew a lot of compressed air thru each opening. I work at a truck dealership. That helps.

I have the same problem. Do you have pictures of your safety wire technique? Is it safe to seal the hole permanently?

I have the same problem. Do you have pictures of your safety wire technique? Is it safe to seal the hole permanently?

I do not have any pictures but the bolt is drilled along with a hole in my Works Connection skidplate. Run safety wire between them and the bolt will never come out, it is not permanent - cut and replace the wire at every oil change.

Here is a quick little how to you can follow:

Same problem on my sons 08. We just re-tapped the hole one size larger in standard thread (American). Used grease on the tap to catch any metal chips. Cut about half a turn at a time them removed tap, cleaned tap then re-greased and repeat. Use a good oil washer so you don't have to over tighten.


i have repaired several of these due to overtghtening,i use a timesert-insert and that is bulletproof repair.the insert is made of steel and will not strip out like the aluminum threads need to remove the oil tank to install the insert,and be sure to clean it out good before you re-install the oiltank.timesert kits are availible through the wurth company,the size is a 6mm by 1.0 thread get several inserts in the kit,imo it is the best way to repair your oiltank.good luck and keep us posted.

I ended up running a 1/4inch steel bolt in the hole. I first checked the hole to see if there was any threads left and to see if the coil of aluminum i pulled off the bolt was all the threads that were missing, I then ran the 1/4 inch bolt ( it is half way between 6-7 mm with the origional bolt was 6mm) the bolt cut new threads without making any metal bits. Repair done without any hassle!!

Thanks for all the responses everyone! I've been busy through the week but plan to get her fixed this weekend. Will let you all know how it goes.

The tank is fixed to the frame with 3 bolts real easy to get off the bikr. The wire screen is at the bottom of the tank to trap the alumnium shavings. The next size bolt is 7mm witch is the same pitch as the original 6mm bolt. You probably could run a 7mm tap with out drilling it out with the appropriate drill which is 6mm with no issues.

use a copper washer on the bolt after what ever repair you make.

use a helicoil kit v. simple and effective repair.

Also iv been running an oil removal/conversion kit on my 06 YZ250F since 07 and id rstrongly recommend one - less chance of burning clutches out as the oil stays in the bottom end!

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